Mechanisms of Statin-Induced Myopathy

The advent of the HMG-CoA reductase inhibitors, or statins, in the 1980’s as highly efficacious agents for the lowering of low-density lipoprotein-cholesterol (LDL-C) revolutionized treatment of hypercholesterolemia, a long established risk factor for premature coronary heart disease. Indeed, a recent prospective meta-analysis of data from more than 90 000 participants in 14 randomized clinical trials revealed that a statin-mediated reduction of 1 mmol/L (40 mg/dL) in LDL-C that is sustained for 5 years may produce a proportional reduction in major vascular events of some 23%.1 Greater reductions in LDL-C, which may be attained with intensive statin therapy as exemplified in the recent Pravastatin or Atorvastatin Evaluation and Infection Therapy–Thrombolysis in Myocardial Infarction 22 (PROVE IT-TIMI 22), Treating to New Targets (TNT), and Reversal of Atherosclerosis with Aggressive Lipid Lowering (REVERSAL) trials involving use of atorvastatin (80 mg/d), produce larger reductions in vascular disease risk.2–4 Importantly, risk reductions are proportional to the absolute reduction in LDL-C1, and moreover clinical benefit may be apparent with intensive statin treatment as early as 30 days after initiation in acute coronary syndrome patients, with significant decrement in cardiovascular morbi-mortality.5 See page 2560 Statins not only exhibit a remarkably high benefit to risk ratio, but are equally characterized by a safety profile with excellent tolerance.6,7 Nonetheless, statins may exert toxic effects on skeletal muscle which are generally referred to as myopathy, and whose overall incidence is typically